The information I have comes from my sister Merry who did the research but I think I can help. My grandfather Gerald Griffin BLUE married Mary Holmes LEDLIE on 6/16/1913 in Glendale California. According to my sister Merry, Mary Ledlie's parents were James Crawford LEDLIE and Milly (Millie?) HANLEY. Up until now, I have not heard of anyone in our family being in Australia.
Gerald Griffin BLUE and Mary Holmes LEDLIE apparently met in Ireland so I think your suspicion that James Crawford LEDLIE and Millie HANLEY returned to Ireland at some point is correct.Feel free to contact me and we'll compare notes.